[GRASSLIST:8390] Re: ps.map resolution

[Hamish]

Hi Ian,

> Hi all, I don't think this has been discussed on the mailing list 
> before, sorry if it has.  Is there any way to increase the resolution 
> of a raster using ps.map?
> 
> As near as I can tell, all rasters come out at 72 dpi.  My
> work-around so far has been to use ps.map, then double, triple, or
> quadruple my scale on a huge page, then use some other software to
> scale that back down to increase the resolution of the raster within
> the postscript file.  This gets cumbersome for large maps.

ps.map uses the current region settings to determine the raster 
resolution. They will only get resampled to 72 dpi if you convert
to PDF etc. Now PostScript positioning works in units of 72dpi*, but 
you can have higher resolution rasters embedded within them.

[*] thus a font size of 10 is actually 10/72 inch tall when sent to the
printer; a font size of 72 is an inch tall; etc.

Just use `g.region rast=map` before ps.map to set the resolution and
bounds to the full resolution of the raster map. Mind the file size as
the .ps file doesn't do any compression.


> Using d.out.whatever can yield the same resolution as the screen 
> however the scale can't be set.
> 
> Any ideas?

One way via the display monitors is to use the PNG driver after setting
GRASS_WIDTH and GRASS_HEIGHT shell variables to the same as the region
columns and rows values.

e.g.

g.region -g rast=mapname
export GRASS_WIDTH=...
export GRASS_HEIGHT=...
d.mon start=PNG
d.rast ...
d.barscale at=...
d.mon stop=PNG




Hamish